This invention relates to telephone call monitoring apparatus for monitoring a subscriber's telephone at the subscriber's location.
One of the objects of this invention is to provide a telephone call monitoring apparatus that is capable of efficiently and effectively determining the duration of telephone calls made from the subscriber's telephone and providing printed information concerning the telephone numbers called and the duration of the calls.
A further object of this invention is to provide a very inexpensive telephone call monitoring apparatus that is capable of monitoring a subscriber's telephone to determine the telephone number and the length of period of the calls.
An additional object of this invention is to provide visual display information to the person making a telephone call to indicate the telephone number being called and a running elapsed time of the telephone call and further being able to record the information on printed material.
A still further object of this invention is to provide a telephone monitoring apparatus that is capable of determining the length of time of the telephone call without receiving any signal from the central exchange indicating that the called telephone has been answered.
A still further object of this invention is to provide a telephone call monitoring apparatus that is capable of being connected to the telephone line without adversely affecting the central telephone system or a subscriber's telephone.
These and other objects and advantages of this invention will become apparent upon reading the following detailed description of a preferred embodiment.